Reading Comprehension.
Directions: Read the following passage. Choose the best answer from the four choices marked A, B, C and D for each question.

     They earn and spend, buy and sell, work and play. It's a mass of individuals, struggling to satisfy often-conflicting goals, who set the pace for the American system. 

     Whether the nation's huge business machine sputters or steams ahead depends on millions of individual consumers, the real “bosses” of the American economy.
     People’s decisions on where to live and work，what to buy or pass over, how much to save are at the heart of the free market system. Business and government take their cues from consumers, changing plans to meet their wants and needs.
     Everyday, the nation's 218 million consumers spend more than 3 billion dollars. Their purchases account for almost two-thirds of all the money spent each year, with government and business responsible for the rest. The trouble is that while people's needs are almost endless, their incomes aren’t.
     Where money goes? About 70 percent of the average household's spending goes for necessities such as housing, food, clothes and health care. To be able to afford these items and still have money left for nonessentials such as travel and entertainment, most families find themselves economizing and watching their pennies. The same problem of matching limited resources with seemingly endless demands confronts businesses and public agencies.
     That is what the economy is all about—making choices on how to use limited resources of money, manpower, machinery and materials, whether it involves a shopper deciding what to buy in the supermarket or a manufacturer deciding what line of goods to produce.
     Choices made in the economy involve a continuous tug-of-war between consumers and producers over price. 

     If many businesses are offering a product and there is plenty of it to satisfy the needs of all consumers, a producer will be forced to sell at a price not far above costs in order to keep from being stuck with a lot of unmarketable supplies. This is why ,for example, prices fresh fruit and vegetables drop during the summer months when such produce is in great number.
     There is a natural ceiling on price, but it differs from one buyer to the next, depending on how much each can afford to pay and how badly he wants to buy. If a company prices its goods or services too high, some consumers will decide they're getting too little value for the money and will put off buying. "It’s not worth that much’’ is the view heard in such situation. 

     But if a respected brand of clothing or appliance is marked down during a sale, the reaction may be just the opposite: a rush of purchases. Why? "It’s a good buy for the money.”